This randomized phase III trial is studying gemcitabine hydrochloride, docetaxel, and bevacizumab to see how well they work compared with gemcitabine hydrochloride, docetaxel, and a placebo in treating patients with advanced or recurrent uterine leiomyosarcoma. Drugs used in chemotherapy, such as gemcitabine hydrochloride and docetaxel, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Bevacizumab may also stop the growth of tumor cells by blocking blood flow to the tumor. It is not yet known whether gemcitabine hydrochloride and docetaxel are more effective when given with or without bevacizumab in treating uterine leiomyosarcoma.